Fluorescent lighting unit



J. E. HOLMES FLUORESGENT LIGHTING UNIT v Filed `March v8, 1944 Aug. 20, 1946.

5 Sheets-Sheet 1 Z5-@banjo 7 Aug. 20, 1946. l v- J. E. HOLMES I LUOJRESCENT LIGHTING UNIT Filed March 8,- 1944 3 Sheets-Sheet 2 Y wMQL-i;

Aug. zo, 1946.

. J. E. HOLMES Filed Maman 8, 1944- 3 sheets-sheet s Tipea/07" .l

" HM @MM- Patented Aug. 20, 1946 UNITED STATES PATENT OFFICE FLUORESCENT LIGHTING UNIT John E. Holmes, Auburndale, Mass.

Application March 8, 1944, Serial No. 525,531

6 Claims.

This invention relates to a fluorescent lighting unit particularlyadapted for illuminating the interior of a show case or the like.

The invention has for an object to provide a novel and improved fluorescent lighting unit of the character specified in which provision is made for mounting the fluorescent lamp in a novel and improved manner to provide minimum liability of arcing or grounding from the terminals and whose structure enables it to conform in all respects to the regulations adopted by the National Board of Fire Underwriters.

With this general object in` view, and such others as may hereinafter appeanthe invention consists in the lighting unit and in the various structures, arrangements and combinationsV of parts hereinafter v,described and particularly defined in the claims at the end of this speciiication.

Inthe drawings illustrating the preferred ern--V o'cdiment4 of the invention, Fig.l 1 is a front elevation of a show case embodying the present fluorescent lighting unit, some of the parts being broken away and shown in cross section; Fig. 2 is an enlarged cross sectional view in side elevation taken on the line 2 2 of Fig. 1; Fig. 3 is an enlarged detail' view in longitudinal cross section of a terminal housing embodied in the present lighting unit, the housing beinglshown in its extended position and with one end of the lamp inserted; Fig. 4 is asimilar View with the housing shown in its retracted position and with the lamp disconnected; Fig. 5 is ra perspective view of one end of the lighting unit as embodied in a show case, some of the parts being shown sepularly adapted for use in illuminating the interior of a show case or the like and in which provisionv is made for mounting the lighting unit in a novel and improved manner whereby to provide a a Vsimple Aand eicient structure for detachably supporting the contact ends of the iiuoresA cent lamp in engagement with the terminals pro-`Y vided therefor, and Whose structure is such-that the liability of inadvertent arcing from the terminals is reduced to a minimum. Y

'In accordance with .the present invention, the

illustrated lighting unit includes a pair of extensible socket members comprising safety hous` ings Whichmay be supportedat each end of theV show case or other similar unit to be illuminated and whichA are capable of retraction and extension to permity insertion and removal of the elongated fluorescenty lamp, and whose construc- J tion is such as to maintain a safe arcing distance from thel terminal connections to the exterior of the safety housing at all times.

In the preferred form of the invention, as embodied in a showcase, the lighting unit includes a reflector or shield which may and preferably will comprise the front rail thereof, forming a part of the frame of the show case, and supporting the adjacent edges of the top and front glass panels. The ends of the show case may and preferably will be constructed to provide a hollow interior to receive and conceal the wires leading from the supporting sockets.

Referring now to the drawings, the present lluorescent lighting unit, indicated generally at I0, is preferably illustrated as embodied in a show',

case I2 and includes an electric discharge tube or fluorescent lamp I4, preferably of the cold cathode type which is arranged to be operatively supported at either end in a pair of safety housings, indicated generally at I5, and preferably mounted at each end of the show case. `The safety housings I5 may and preferably will be made `of porcelain, glass, Vplastics or other dielectric material, and, as herein shown, each housing includes a `stationary tubular member IB in which provision is made for connecting a .terminal wire I8, and a longitudinally movable tubular member 2,0 provided with a socket 22 for receiving one end of the fluorescent lamp. The. stationary member I6 as herein illustrated is prounitto be hereinafter described.

As best shown in Figs. 3 and 4, the insulated terminal wire I8` is connected to an adapter 30 which is supported within a central opening 32 formed in a centrally disposed and longitudinally extended cylindrical portion 340i the stationary member I6. The baredend portion of the termi'- nal wire I8 is preferably extended through a central bore V35 of the adapter and soldered at the extended end in a countersunk portion provided 3 Y therefor. The adapter 39 is provided with a flanged head 38 which is seated against a portion l of reduced diameter formed within the opening .32, the other end of the adapter extending through said portion, and is provided with eX- `ternal threads for cooperation with a second adapter 32 which is internally threaded. The secondadapter 42 is also provided with a Yiiangedv head 4.4 which engages with the top of the cylindrical portion l34 of the stationary housing mem- Vber I5 whenV the two adapters are screwed up tight as illustrated in Figs. 3y and 4. v Y M As herein illustrated, the socket member 22,

which may be ofthe split fuse holder type for yieldingly engaging the end of the iiuorescent lamp, may and preferably will be permanently fixed within the tubular housing member Zyl. The f1 attached end of the socket is formed of 'a reduced diameter and extended through a collaredplorf^ tion 46 formed in the tubular member, the shouldered portion 48 of the socket resting against one edge off the collaredportion and the extended .end offthefsocket being hushed over or spun against theopposite edge Vofthe collar as indicated atv 52.' As herein shown, the outer end of the con tact pin 5d -is disposed withinthe socket 22 and` is; providedV with an ,enlarged head 5.6 for engagement withan inwardly flanged portion 58 atfthel bottom of the socket member, as clearly shown in Figs. 3. and 4l Thus, in operation, when the socket housing member 21.0 is extended to operfatively` engage theend of the lluorescentV lamp, as'sh'own in Fig. 3, the contact pin 54 is moved forward in the bushing 52 while maintaining Contact therewith, When the socket housing member- 2 !l is retracted to the. full depth of the annular recess 24., as shown in Fig. 4, the female member 52 is arranged to pass through the opening in the bottom of the socket 22 formed by the inwardly flanged portion l53 the male member being moved back by the engagement Yof the endof the lamp during the shifting'thereoi in the removing operation, or, the male member may remain in' its'extended position to be again engaged by the bottom .of the socket when the latterris `moved forward intooperative engagementwith the. lamp.

The present fluorescent lampY housing is de-v signed to conform with the standards adopted by the National Board of Fire Underwriters for terminalsand receptacles for gas tubing operating at high voltages which require that the live ter-v minals andconductors shalljbe so supported asto maintain a separation of atleast 11/2 inches between the conductor and, any grounded metal. The present lighting unitfpreferably employs a cold `,cathode type of iiuorescent lamp operative at around 15,000 vous andfisfusually providdwitn ai` shield or `reflector which may befmade of metal. Thus, inthe above described Vembodiment ofthe invention, the socketmemberZis disposed at a suiiicient depth'inV the housing member. 20 so that the'distance 'from the top ofthe live socket to the outer end of the housing member 20 is equal to or in excess of the minimum arcing distance required by the National Board of Fire Underwriters. Also, the stationary housing member I6 is constructed to dispose the vend oi the flangedV .such portion and upwardly between the outer surface of the portion 26 and the inner surface of the .tubular outer wall of the member I6 to the outer edge of said member I6.Y In order to assure` the maintenance of a safe arcing distance through the above dened path at all times lduring the extension or retractionfof the sliding lmember 20, the annular recess 24 is made of sucient depth `and the'telescopically engaged portion Z6 is made of sufficient length so that whenY the movable member 2li is moved to its position of maximum extension into operative engagement with the lamp, the airspace through the above dened path will-.equal or exceed the minimum distance required.

Provision is also made for breaking the contact between the male and female connecting members 5,2, 54 in the event that the movable member 2i! is inadvertently extended beyond the z-equi'redV safety distance and tothis end the members 5,2, 5.4 are so proportioned. as to separate upon suchV abnormal projection of the housing. Howeven as illustrated in Fig.Y 3, a suitable stop pin ilrrnay and preferably rwill be provided in the end .of the male member 54 forengagement with the closed Vend of a slotted portion 51 in the femalemember v52 to prevent extension of the movable -member 2!! beyond the required safe distance to thus'positively assure the maintenance of a safe arcing 'distance from any live conductor to a Y possible ,grounding pointadjacent the outside @the housng- Y From the description .thus far it will be .ob-

served that the present .safety housing provides a simple and eflicient unit to permitextension andcontraction into and out of operative engagement Withthe `contact ends-.or-the uorescent lamp and Y' whose construction is 'such` as to maintain the maximum required separation between any portions of the high voltage conductorsto a possible grounding :wint outside the shielding housing andthat any `type of metal vreflector o-r metal supe porting structure for the housings may be used without danger of arcing from the live conductors. I

Referring now to Fig. 1, the present fluorescent lighting unit is preferably illustrated as enflbtld.

ledl in the'ShQWvcaseflZ having top. and .front glass panels En, 16,2 and hollow .end panels 54.

Asherein shown the saietyhousings .i5 'arey y mounted in. internally threaded receptors in whiplrthey threaded .end 2,8 of the housings may bevreceived.. VThe receptors maybe Vsecu-red 'to the inner wall 68 of each@ end panel 6g byscrews: l0. In order to provide a1more1iigidf-attachmentto the. Ypanels and to assure proper alignment; the

receptors may beV proyidedwith shouldered por-J tionsaflzzextended'into a bore in thel'inner Wall lThe. receptors. :may ybe. made. of a 'plastic or other suitable dielectric material, or, they may be made of metal since the construction of the housing is such as to reduce to a minimum any danger of arcing from the live conductors. .As herein shown, each receptor 66 is preferably disposed in theupper front 'corner of the end panels B4 ofthe show case, and, as best shown in Fig. 5, each receptor is rabbeted as indicated at 14, around its inner edge to receive the ends of vthe Afront rail'16 of the show case frame, the rabbeted portion conforming to the contour of therail to form a flush exterior surface. The rail 16 may be secured to the receptors by screws 18 andas thus constructed the front rail serves as a reflector or shield for the elongated lamp. The reflector rail may be made of a suitable plastic materialor maybe made of metal. When Vmade ofmeta'l; the receptors 66,'a'nd the reflector rail 'lmay and: preferably will be suitably grounded. 1 The frontV rail 16 is also preferably designed to support the front edge ofV the top glass panel 60 in a recess 80 formed by an offset 82 in the upper lwall 84 of the rail, and, a grooved portion 86 formed integrally with the front wall 88 of the rail is provided to receive the upper edge of .the-front glass panel B2 as illustrated. The reflector rail is preferably designed lto effect illumination of the interior of the show case and to serve as a shield to prevent any glare from the lamp from being directed toward the observer standing in front of or in the rear of the show case.

From the above description it will be observed that when thus embodied in a show case the insulated wire leads I8 may be drawn through thefhollow end panels 64 to thus conceal the lead wires from view and to leave the interior of the show case free from wiring or wiring conduits. It will also be observed that the reflector rail conceals the safety housings from the View of the observer thus providing a compact and efiicient unit for embodiment in a show case.

In some instances, it may be desired to support the ends of the safety housings I5 independently of the ends of the show case, and, for this purpose, as illustrated in Fig. 6, a modified form of support may comprise a receptor 90 provided with an elbow 92 formed integrally therewith and arranged to receive a' conduit 94 through which the wires are extended. The contour of the modified receptor may and preferably will be such as to fit snugly within the front reflector rail and may be attached thereto by screws 18, as above described.

Likewise, the present iiuorescent lighting unit may be supported within the show case independently of the front rail. In such instances, the receptors 9D may be used and a separate reflector section attached thereto. Such units may be supported in any position within the show case remote from the front rail or frame of the show case. Y

As illustrated in Fig. 4, the movable housing member 20 may and preferably will be provided with an integral lug 2| extending radially therefrom for convenience in sliding the housing member into and out of operative engagement with the ends of the fluorescent lamp.

From the above description it will be seen that the extensible safety housing embodied in the present lighting unit comprises a shielding member for the live conducting elements supported therein and that the construction of the housing is such as to maintain at least a predetermined minimum unshielded distance or air space fromthe live conducting elements to a possible grounding point adjacent the,v outer surface of thehousing, such as the supporting elements or the lreflector rail whereby to reduce` to a minimum liability of arcing from said elements to such possiblegrounding points. y

While the preferred embodiment of theginvention has been herein illustrated and described it will be understood that the invention may be embodied in other forms within the scope of the following claims.

Having thus described the invention, what. is claimed is:

1. In a fluorescent lighting unit for use in a show case' or'thelike having top and front glass panels and hollow end panels, a pair of safety housings comprising extensible shielding 'membersfor operatively supporting thev ends of'a fluorescent lamp, means for supporting said safety housings comprising a pair of receptors attached to said hollow end panels, said hollow end panels being arranged to receive and conceal' the Wiring from the unit, a reflector rail comprising the front rail o-f the show case frame attached to saidreceptors and disposed in close proximity to said safety housings, said front rail having provision for supporting the adjacent edges of said top and front glass panels, live conducting elements of relatively high voltage supported within said housings, the arrangement being such that said safety housings may be longitudinally contracted to permit insertion of said lamp and thereafter extended into operative'position, with all conductive material within said' housings shielded at all times.

2. In a fluorescent lighting unit, a safety housing for operatively supporting the end of a fluorescent lamp,4 comprising: an insulating member having an opening therein adapted to receive an insulated cable having a bared end, so that the insulated portion of said cable will extend to 1a point substantially within said insulating member; a' conducting member vsecured withinsaid insulating member for connection Awith the bared end of said insulating cable; an elongated hollow insulating member telescopically associated with said first named insulating member; a lamp socket secured within said hollow insulating member spaced inwardly from both of the ends thereof; and means maintaining an electrical connection at all times .between said conducting member and said lamp socket, the arrangement being such that said safety housing may be longitudinally contracted to permit insertion o-f said lamp and thereafter extended into operative position, with all conductive material within said housing shielded at all times.

3. In a iiuorescent lighting unit, a safety housing for operatively supporting the end of a uorescent lamp, comprising: an insulating member having an opening therein adapted to receive an insulated cable having a bared end, so that the insulated portion of said cable will extend to a point substantially within said insulating member; a conducting member secured within said insulating member for connection with the bared end of said insulating cable; an elongated hollow insulating member telescopically associated with said rst named insulating member; a lamp socket within said hollow insulating member spaced inwardly from both of the ends thereof; an elongated bushing secured to said conducting member and an elongated pin sldably received by said bushing and engageable Iwith said lamp socket, said bushing and said pin malni tairiiii'gat al1 'times 'an electrical connection bei tween said conducting member and said lamp socket, the' arrangement being such that vsaid safety housing' maybe longitudinal]'y''rbontracted` to permit insertion ofsa'idlamp and'theieafter 'extended into operative position, withv all condiictive material within said 'housing shielde'd Yat Vhollow insulating member telescopcally associatediiwith vsaid 'first-named insulating member; a lamp 'socket within said hollow insulating member spaced inwardly from both ofthe ends thereof.; an' elongated bushing secured to said conducting member; an elongated pin slidably receivedby said bushing and engageable with said lamp socket; and a 'stop member mounted von said v-p'in and engageable with' a portion of said bushing 'for limiting the outward movement of said pin with respect to said bushing, said bushing and said pin maintaining at all times an electrical connection between said conducting memberrand said llam-p socket, the 'arrangement being such that said safety housing may be longitudinally contracted to permit insertion of said lamp and thereafter extended into operative position, Withgall 'conductive material within said housing shielded-at all times. l

5. In-afluorescent lighting unit, a safety housing for operatively supporting the end `of a fluorescent lamp, comprising: Ya hollow insulating member having an opening therein adapted to receive an insulated cable having a bared end, so that thevfinsulated por-tion of said cable will extendeto a vpoint substantially within Asaid hollow insulating member; a conducting member secured within said hollow'insulatin'g member for connection with lthe bared end of said insulated cable, a secondA 'hollow insulating member telescopically associatedrwith said first-'named hollow insulating member; a'lamp socket Within said sec'-` ond-named hollwfinsulating member spaced inwardly from both of the ends thereof; and means maintaining an electrical connection at all times between said conducting member and said` lamp socket, `the arrangement "being such that `said safety housing may loe'longitudinally vcontracted to permit insertion of said lamp and thereafter extended into operative position, with allV conductive material within said housing shielded at al1 times. f

6. In afluore'scent lighting unit, a safetyhouse Y ing for operatively supporting'the end of `ya fluo-k rescent lamp, comprising: an insulating'l :member Yhaving a longitudinally rextending opening disposed centrally thereof adapted to receive an insulated cable having a bared Vend 'so thatthe Y insulated portion of vsa'idcable 'extends substane tially within said insulating member, Vand a lon'-L gitudinally extending annular recess arranged concentrically with respectV to said opening; a conducting member secured within `said 'insulating member for connection with the bared end of said insulating cable; an elongated hollow fin sulating member having a longitudinally 'exe tending portion slidably received in said-annular recess of said first-named insulating member; a lamp socket secured within said hollow insulating member spaced inwardly from both vof the ends thereof; and Ymeans maintaining an electrifcal connection at all times between said cionducting member and said `lamp socket, the yarrangement 'being such that said safety housing may be longitudinally contracted to permit in--y sertion of said lamp and thereafter extended into operative position, with 'all conductive material within said-housing lshielded at all times.

Y JOHN E. YHoLMias.' 

